Trimmer device



March 11, w. F. ADAMS v 2,826,150

TRMMER DEVICE Filed Nov. 2, 195,6

p 2,826,160 Patented Mar. 11, 1958 ddee TRIMMER DEVICE William F. Adams, Philadelphia, Pa.

Application November 2, 1956, Serial No. 620,006

7 Claims. (Cl. 112-252) This invention relates generally to thread-severing and -holding devices for sewing machines, which devices are generally termed trimmers, and are commonly employed in buttonholing, lacking, and similar needlework operations.

As is well known to those versed in the art, conventional trimmers are generally unsatisfactory for numerous reasons. In particular, prior thread trimmers are relatively complex and delicate in constuction, expens've to manufacture, and subject to frequent damage under normal conditions of use. Usually, a damaged trimmer is incapable of being repaired unless returned to the manufacturer, which causes inconvenience, expense, and delay. Another diiliculty experienced with prior thread trimmers is their frequent breakage of sewing needles, each occurrence of which is extremely costly, as a broken needle severely damages the garment being operated upon.

Accordingly, it is the general object of the present invention to provide a thread-trimming device which overcomes the above-mentioned disadvantages of the prior art, is extremely simple in construction and durable in use, and which can be manufactured by substantially automatic mass-production methods to effect substantial reduction in their price.

lt is a further object of the present invention to provide a thread trimmer having the advantageous characteristics mentioned in the preceding paragraph, which is rugged in construction so as to be trouble-free in operation, and which, if it should be damaged, is capable of being quickly and easily repaired without return to their place of manufacture.

Other objects of the present invention will become apparent upon reading the following specification and referring to the accompanying drawings, which form a mateinafter described, and of which the scope will be indiy cated by the appended claims.

ln the drawings:

Figure 1 is an inverted or bottom plan View showing the underside of a sewing-machine throat plate and a trimmer device of the present invention assembled there with, with the trimmer in an initial position of its operative movement;

Figure 2 is an inverted plan view similar to Figure l, showing the trimmer in an intermediate position of its operative movement;

Figure 3 is an inverted plan view similar to Figures l and 2, and illustrating the trimmer in a later stage of its operative movement;

Figure 4 is a partial sectional view, somewhat enlarged, taken generally along the line 4 4 of Figure 1; and

Figure 5 is a perspective view showing a trimming dey vice of the present invention apart from a sewing-machine throat plate.

Referring now more particularly to the drawings, there is illustrated therein a trimmer device, generally designated 1t), mounted on the underside of a throat plate 11; and, an actuating rack 12 is operatively connected to the trimmer device.

The throat plate 11 is defined between generally flat, parallel spaced lower and upper surfaces 14 and 15, respectively, the throat plate being inverted in the drawings. Formed in the throat plate 11 is a hole or aperture 16, extending generally normal to and opening through the plate surfaces 14 and 15. An eyelet or bushing 17 may be inserted in the throat-plate hole 16, and terminates at one end substantially liush with the surface 14 of the throat plate.

The trimmer is mounted on a pivot pin or bolt 19 which has its upper end ixedly secured, as by threaded engagement or other suitable means, in the throat plate 11 at a point spaced from the needle hole 16. The bolt 19 depends from the underside of the throat plate 11, substantially normal to the latter, and is provided on its lower end with an enlarged head 26. An upwardly facing shoulder 21 extends circumferentially about the bolt 19 on the head 2t). Surrounding the bolt 19, between the throat plate 11 and shoulder 21, is a tubular sleeve or spacer 22, which enables the bolt to be screwed up tight in the throat plate with its head properly spaced below the throat plate.

A pinion or gear 24 is rotatably circumposed about the sleeve 22 of the bolt 19 adjacent to the bolt shoulder 21, and is formed with a stepped tubular hub surrounding the sleeve 22 and extending to the undersurface 14 of the throat plate 11. More specifically, the hub 25 includes a reduced, tubular end portion 26 surrounding the sleeve 22 adjacent to the throat plate 11, and an enlarged annular portion 27 surrounding the sleeve, located between and preferably integral with the reduced portion 26 and gear proper 24. Thus, the enlarged hub portion 27 combines with the reduced hub portion 26 to define an annular, upwardly facing shoulder 253.

A carrier member, generally designated 30, includes a generally annular portion snugly circumposed about the reduced hub portion 26, in abutting engagement with the shoulder 28 and closely adjacent to the undersurface 14 of the throat plate 11. The carrier also includes an extension bar or arm 32 extending substantially radially outward from the annular portion 31, in substantially coplanar relation with respect to the latter, so as to have its upper surface closely adjacent to the underside of the throat plate 11. As seen in Figure 4, the extension arm 32 of the carrier 30 extends beyond the gear 24 and terminates at its outer end considerably short of the needle hole 16. A generally rectangular recess 33 is formed in the undersurface of the carrier arm 32 and opens outward through the distal end of the arm. ln order to rigidly secure the carrier to the gear 2- for rotation therewith about the axis of bolt 19, a plurality of fastener pins 35 may extend through the gear and they carrier portion 31.

Detachably secured to the carrier arm 32, and extending outward beyond the distal end thereof is a platelike member, generally designated 38, disposed in contiguous facing relation with the throat-plate surface 14 and swingable in said relation with the carrier 39 about the axis of pin 19 across the needle hole 16. Y

In particular, the plate member 38 includes a generally rectangular attachment portion or tab 39 configured to conformably seat in the recess 33 of the carrier arm 32 and removably secured therein by a fastener 42.` Extending from the attachment portion 39 beyond the outer end of the carrier arm 32, inclined generally upward and away from the carrier arm, is an offsetting plate-member portion 49. A main plate-member portion 41 extends from the inclined, otfsetting portion 40 outward away from the distal end of the carrier arm 32, in closely adjacent facing relation with the throat-plate surface 14.

As best seen in Figure l, the major plate portion 41 terminates at its outermost edge 43 beyond the needle hole 16 of the throat plate 11, so that the major plate portion is swingable across the needle hole upon rotation of the plate member 38 with the carrier. Formed in the major plate portion 41, in substantial alignment with the carrier 30, radially of the pivot pin 19, is a through opening or hole 415 which is appreciably larger than and is located to underly the needle hole 16 in one position of pivotal carrier movement. It will be observed that the hole 44 is of appreciable lateral dimension, so as to register with the needle hole 16 through an are of carrier movement. Located on one side of the right side as seen in the drawings, and spaced from the hole 44, the plate portion 41 is formed with a through opening, hole or cutout 46 extending generally inward toward the carrier 30. Stated otherwise, a through opening or hole 46 is formed in the plate portion 41 at a radial distance from the pin 19 substantially equal to that of the hole 44, and opens generally outward away from the carrier 30. Thus, the openings 4d and d6 are spaced laterally from cach other by a region 47 of the plate portion 41 which is disposed in contiguous facing relation with the underside of the throat plate 11.

Extending from the plate region 47, preferably integral therewith and intermediate the openings 44.- and d6, is a linger or catch 49. The linger 49 may have its free end pointed, as illustrated, and extends generally tangential to motion of the carrier Sil and plate member 33. As best seen in Figure l, the finger or extension 49 extends generally toward the right, and is located outward or in front of the cutout 46 and beyond the hole 16 radially from the pivot 19. In Figures 4 and 5, it will be seen that the extension or linger 49 is bent to extend obliquely downward away from the throat plate 11.

Disposed on the right of the opening 46, as seen in the drawing, the main plate portion 41 is provided with a preferably integral arm or extension 51, substantially coplanar with the main plate portion. More particularly, the arm 51 is located on one side of the cutout 46, defining a bounding edge portion of the latter, and has its free end portion 52 bent or crooked away from the cutout 46. Thus, the arm 51 is somewhat hook-shaped and disposed on one side of the cutout 46 with its convex side facing toward and its concave side facing away from the latter.

The actuating member 12 includes a reciprocable bar 55 movable in timed relation with respect to a motion of a sewing needle through the hole 16. The bar 55 carries a toothed rack 56 in meshing engagement with the gear 24, to thereby elfect swinging movement of the trimmer 10 about the pivot pin 19 in timed relation with respect to operation of a sewing needle.

Operation The sewing procedure commences with the trimmer 10 in the position of Figure l, s0 that the hole 44 of plate member g8 is in registry with the needle hole 21.6 for receiving the tirst stroke of the sewing-machine needle. The actuating rack 56 moves upward during the stitching procedure to swing the trimmer 1t) clockwise, as seen in Figures 1 3. The plate region 47 located between the openings 44 and 46 engages with the free end of the sewingneedle thread upon upward movement of the sewing needle at the end of the iirst stitch, to thereby clamp the free needle-thread end against the undersurface 14 of the throat plate 11 and prevent its withdrawal through the needle hole 16. By the time of the second stitch or stroke 0f the sewing needle, the cutout 46 is located in registry with the needle hole 16 to receive the needle, as illustrated in Figure 2. Continued movement of the trimmer 10 in the clockwise direction, and specifically, movement 'di' of the plate region 47, will permit release of the needlethread end from between the plate region and throat plate 11. rl`his release of the needle-thread end may occur during the second needle stroke or stitch, or subsequent thereto, as the lock stitching prevents undesired withdrawal of the free thread end.

At least the second stitch, and preferably, the third and fourth stitches occur with the plate-member cutout 46 in registry with the needle hole 16 to receive the sewing needle.

Upon continued movement of the trimmer 10 about the pivot 19, from the position of Figure 2 to that of Figure 3, the bobbin thread rides over the convex side of the arm 51; and, subsequent stitching occurs with the trimmer in the position of Figure 3 or swung clockwise further beyond the needle hole.

At the end of a desired number of stitches, the trimmer 10 swings quickly in the counter clockwise direction, whereupon, the arm 51 catches the bobbin thread and severs or cuts the latter, and the extension 49 catches in the needle-thread loop of the last stitch to sever the needle thread as the sewing needle moves upward. This completes the operating cycle.

From the foregoing, it is seen that the present invention provides a thread-trimming device for sewing machines which fully accomplishes its intended objects, and is well adapted to meet practical conditions of manufacture, maintenance, and use.

Although the present invention has been described in some detail by way of illustration and example for purposes of clarity of understanding, it is understood that certain changes and modifications may be made within the spirit of the invention and scope of the appended claims. For example, while it has not been found necessary in practice, either or both of the plate extension S1 and 49 may be provided with knifed edges for cleaner threadcutting action.

Wiat is claimed is:

l. A thread trimmer for attachment to the throat plate of a sewing machine, said trimmer comprising a platelike member adapted to be mounted on the underside of said throat plate for swinging movement across the needle hole of the throat plate in facing relation with respect to the throat plate, said platelike member being formed with a first through hole adapted to receive the first stroke of the sewing needle upon swinging movement of said member in one direction, said member being formed with a second through hole disposed on one side and spaced from said first hole for receiving at least the second stroke of the sewing needle upon continued swinging movement of said member in said one direction, the portion of said member between said holes serving to hold the needle-thread end against said throat plate on the second needle stroke and to subsequently release said needle-thread end upon continued movement of said member in said one direction, an arm projecting from said member on said one side of said second hole for swinging movement with said member and adapted to sever the bobbin thread upon movement of said member in the other direction, and an extension on said member outward of said second hole adapted to engage in and sever the needle-thread loop of the last stitch upon coninued movement of said member in said other direction.

2. A thread trimmer according to claim l, wherein said second hole opens outward through said plate member between said arm and extension to permit the bobbin thread to ride over said arm upon member movement in said one direction.

3. A thread trimmer according to claim 1, wherein said arm has its free-end portion crooked toward said one side to hook said bobbin thread upon member movement in said other direction.

4. A thread trimmer for attachment to the throat plate of a sewing machine, said trimmer comprising a carrier adapted to be mounted on the underside of said throat 5 plate for swinging movement about an axis normal to said throat plate, a pinion carried by said carrier for driven engagement with timed actuating means of said sewing machine, a plate member carried by said carrier for swinging7 movement across the needle hole of said throat plate in contiguous facing relation with said throat plate, said plate member being formed with a hole adapted to receive a first stroke of the sewing needle upon swinging movement of said plate member in one direction, said plate member being formed with a cutout extending inward toward said carrier on one side of and spaced from said hole for receiving at least the second stroke of the sewing needle upon continued swinging movement of said plate member in said one direction, the portion of'said plate member between said hole and cutout serving to hold the needle-thread end against the undersurface of said throat plate on the second needle stroke and to subsequently release said needle-thread end upon continued plate-member movement in said one direction, an arm projecting from said plate member on said one side of said cutout and having its free-end portion bent away from said cutout and adapted to sever the bobbin thread upon movement of said plate member in the other direction, and an extension on said plate extending from the plate portion between said hole and cutout and terminating in a free end disposed outward of said cutout for engaging in and severing the needlethread loop of the last stitch upon continued movement of said plate member in said other direction.

5. A thread trimmer according to claim 4, wherein the free end of said extension is angulated downward away from said throat plate to facilitate entry into the needle-thread loop.

6, A thread trimmer according to claim 4, said plate member, arm and extension being formed as an interal piece and detachably secured to said carrier.

7. A thread trimmer according to claim 4, said arm extending obliquely away from said cutout to enable the bobbin thread to ride over said arm upon swinging movement of the latter in said one direction.

References Cited in the tile of this patent UNlTED STATES PATENTS 1,651,998 Horton Feb. 4, 1913 1,141,041 Darley May 25, 1915 1,638,785 Ray Aug. 9, 1927 2,474,710 Wood June 28, 1949 2,474,710 Wood lune 28, 1949 

